Ameliorates Ovariectomy-Induced Bone Loss Enhancing Anti-Osteoclastogenic and Immunomodulatory Potential of Regulatory B Cells (Bregs).

Discoveries in the last few years have emphasized the existence of an enormous breadth of communication between osteo-immune systems. These discoveries fuel novel approaches for the treatment of several bone pathologies including osteoporosis. (BL) is a preferred probiotic of choice due to its varied immunomodulatory potential in alleviating various inflammatory diseases. Here, we evaluate the effect of BL in an ovariectomy (ovx)-induced post-menopausal osteoporotic mouse model. Our findings reveal that BL suppresses the differentiation and functional activity of RANKL-induced osteoclastogenesis in both mouse bone marrow cells and human PBMCs. Strikingly, BL-induced Bregs were found to be significantly more efficient in suppressing osteoclastogenesis and modulating Treg-Th17 cell balance with respect to control Bregs . Our µCT and bone mechanical strength data further confirm that BL supplementation significantly enhanced bone mass and bone strength, along with improving the bone microarchitecture in ovx mice. Remarkably, alterations in frequencies of CD19CD1dCD5IL-10 Bregs, CD4Foxp3IL-10 Tregs, and CD4RorγtIL-17 Th17 cells in distinct lymphoid organs along with serum-cytokine data (enhanced anti-osteoclastogenic cytokines IFN-γ and IL-10 and reduced osteoclastogenic-cytokines IL-6, IL-17, and TNF-α) strongly support the immunomodulatory potential of BL. Altogether, our findings establish a novel osteo-protective and immunomodulatory potential of BL in augmenting bone health under osteoporotic conditions.